For centuries great thinkers have debated whether or not humans are born with innate traits like morality and empathy. Some fancied the idea of tabula rasa, believing that infants are blank slates waiting to be written on by parents, society and experience, while others suggest that evolutionary adaptations help shape our brains, providing us with the biological and psychological context for playing nice with others.

In 2007, a study suggested that infants as young as 6 months could tell friend from foe, the study had shown that babies possessed a “moral compass” that was” universal and unlearned.” The infants both 6 months of age and 10 months of age watch two different staged play scenarios. In one, a wooden toy tried to climb a hill. A “helper” toy then assisted the climber. In the second scenario, a “hinderer” toy got in the way and pushed the climber down the hill. When the infants were later presented with the option to choose the “helper” or the “hinderer” toy for play, most went straight for the “helper.” Then a second condition was added, a neutral toy, that neither helped nor hindered the climbing toy, was added to the mix. When asked to choose between a helper and the neutral toy, the infants went for the helper. When asked to choose between the hinderer and the neutral toy, they preferred the neutral toy.

Now a new study suggests that the babies weren’t evaluating the social situation but showing a preference for the toys engaged in more interesting play. Basically, the babies weren’t making judgments on “good” or “bad” toys, but preferred the toys that did more interesting things. While reviewing the data tapes from the previous study researchers noticed that toys bounced up and down at the top of the hill at the end of the helping scene. Toys also collided in some scenarios. And so the researchers repeated the study, manipulating collisions and bouncing in some new trial conditions. Sure enough, they discovered that infant preferences were linked to the bouncing more than the helping. For example, when the toy bounced in the “hinderer” scenario but not the “helper” scenario, babies preferred the bad guy.